Painting systems of this type have a very wide spread, which does not need documented proof. In practice, for which documented proof is missing, the connection of the ring lines to the application device or, what is more frequent, to a plurality of application devices is made in that, when setting up the painting system, branch lines are fitted to the ring lines on site by the mounting personnel and are then connected in a suitable way to the application device or devices. The areas around the branches, at which leaks can possibly occur, must be surrounded by hand with a suitable housing which, for safety reasons, must be gas-tight and liquid-tight. This work serving to connect the ring lines to the application devices and to be carried out by hand is comparatively labor-intensive and inclined to faults. The testing of the tightness of all the connections on-site is complicated. If an existing system of this type is to be converted for a new application and, in the process, new connections to the ring lines have to be produced; this is likewise very labor-intensive and fraught with errors.